Method and apparatus with grid map generation

ABSTRACT

A method with grid map generation includes: determining position information of a moving object corresponding to a first time step based on a position sensor of the moving object; determining detection information of nearby objects present around the moving object corresponding to the first time step based on a radio detection and ranging (radar) sensor of the moving object; selecting a still object in a moving range of the moving object from among the nearby objects, based on the position information and the detection information; updating a point cloud determined based on the radar sensor in a previous time step of the first time step, based on the position information and on detection information of the still object comprised in the detection information of the nearby objects; and generating a grid map based on an occupancy probability for each grid of the updated point cloud.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 USC § 119(a) of KoreanPatent Application No. 10-2021-0097076, filed on Jul. 23, 2021 in theKorean Intellectual Property Office, the entire disclosure of which isincorporated herein by reference for all purposes.

BACKGROUND 1. Field

The following description relates to a method and apparatus with gridmap generation.

2. Description of Related Art

A light detection and ranging (lidar) system may be a detection systemconfigured to measure position coordinates of a reflector by measuring atime used for an emitted laser pulse to be returned after beingreflected. Although the lidar system may be used as a sensor forrecognizing an environment around a traveling vehicle, it may beexpensive in price and need a great amount of computation or operation.

In contrast, a radio detection and ranging (radar) system may be adetection system configured to measure the distance, direction, angle,and velocity of an object by analyzing an electromagnetic wave returningafter an emitted radio wave strikes on the object. The radar system mayhave a lower range resolution than the lidar system, and thus may nothave a high accuracy in recognizing an environment around a travelingvehicle. The range resolution of the radar system may be associated witha bandwidth of a transmission waveform, and the available bandwidth maybe specified under a radio wave act or regulation. A previouslyspecified frequency band for a radar system included 0.2 gigahertz (GHz)near 24 GHz and 1 GHz near 77 GHz. However, the range of use of a radarsystem is increasing as a 4 GHz band of a 79 GHz region is specified.

SUMMARY

This Summary is provided to introduce a selection of concepts in asimplified form that is further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

In one general aspect, a method with grid map generation includes:determining position information of a moving object corresponding to afirst time step based on a position sensor of the moving object;determining detection information of nearby objects present around themoving object corresponding to the first time step based on a radiodetection and ranging (radar) sensor of the moving object; selecting astill object in a moving range of the moving object from among thenearby objects, based on the position information and the detectioninformation; updating a point cloud determined based on the radar sensorin a previous time step of the first time step, based on the positioninformation and on detection information of the still object comprisedin the detection information of the nearby objects; and generating agrid map based on an occupancy probability for each grid of the updatedpoint cloud.

The updating of the point cloud may include: transforming coordinates ofa first point cloud determined in the previous time step, with respectto a position of the moving object in the first time step determinedbased on the position information; generating a second point cloudcorresponding to the still object, based on detection information of thestill object determined in the first time step; and determining anupdated point cloud corresponding to the first time step by accumulatingthe second point cloud with the transformed first point cloud.

The method may include removing the first point cloud determined in theprevious time step.

The detection information may include relative position information ofthe nearby objects with respect to a position of the radar sensor, andthe updating of the point cloud further may include transformingrelative position information of the still object comprised in thedetection information with respect to a position of the moving object,based on a relative position relationship of the radar sensor and themoving object.

The selecting of the still object may include: filtering out nearbyobjects positioned at a height greater than or equal to a preset firstthreshold value corresponding to a height of the moving object, based onrelative position information of the nearby objects comprised in thedetection information; and selecting the still object from among thefiltered nearby objects, based on velocity information of the movingobject comprised in the position information and relative velocityinformation of the nearby objects comprised in the detectioninformation.

The selecting of the still object may include: filtering out nearbyobjects of which an angle formed with the moving object is greater thanor equal to a preset second threshold value, based on relative positioninformation of the nearby objects comprised in the detectioninformation; and selecting the still object from among the filterednearby objects, based on velocity information of the moving objectcomprised in the position information and relative velocity informationof the nearby objects comprised in the detection information.

The updating of the point cloud further may include: setting a region ofinterest (ROI) of traveling of the moving object based on the positioninformation of the moving object; and filtering out a point cloudcorresponding to a still object that is not comprised in the ROI amongpoint clouds corresponding to still objects selected through theselecting.

The generating of the grid map further may include generating a movingpath of the moving object corresponding to the still object based on thegrid map.

The generating of the moving path of the moving object may includegenerating the moving path of the moving object that detours a spaceoccupied by the still object, based on the grid map.

The determining of the position information of the moving object mayinclude determining any one or any combination of any two or more ofvelocity information of the moving object, yaw rate information of themoving object, and global positioning system (GPS) information of themoving object corresponding to the first time step.

The determining of the detection information of the nearby objects mayinclude determining either one or both of relative position informationof the nearby objects and relative velocity information of the nearbyobjects with respect to the radar sensor corresponding to the first timestep.

The point cloud may be generated based on a signal sensed by the radarsensor, and may include a set of one or more points corresponding to thesensed signal in a coordinate system having a position of the movingobject as a reference point.

In another general aspect, one or more embodiments include anon-transitory computer-readable storage medium storing instructionsthat, when executed by one or more processors, configure the one or moreprocessors to perform any one, any combination, or all operations andmethods described herein.

In another general aspect, an apparatus with grid map generationincludes: one or more processors configured to: determine positioninformation of a moving object corresponding to a first time step basedon a position sensor of the moving object; determine detectioninformation of nearby objects present around the moving objectcorresponding to the first time step based on a radio detection andranging (radar) sensor of the moving object; select a still object in amoving range of the moving object from among the nearby objects based onthe position information and the detection information; update a pointcloud determined based on the radar sensor in a previous time step ofthe first time step, based on the position information and detectioninformation of the still object comprised in the detection informationof the nearby objects; and generating a grid map based on an occupancyprobability for each grid of the updated point cloud.

For the updating of the point cloud, the one or more processors may beconfigured to: transform coordinates of a first point cloud determinedin the previous time step, with respect to a position of the movingobject in the first time step determined based on the positioninformation; generate a second point cloud corresponding to the stillobject, based on detection information of the still object determined inthe first time step; and determine an updated point cloud correspondingto the first time step by accumulating the second point cloud with thetransformed first point cloud.

The detection information may include relative position information ofthe nearby objects with respect to a position of the radar sensor, and,for the updating of the point cloud, the one or more processors may beconfigured to transform relative position information of the stillobject comprised in the detection information with respect to a positionof the moving object, based on a relative position relationship of theradar sensor and the moving object.

For the selecting of the still object, the one or more processors may beconfigured to: filter out nearby objects positioned at a height greaterthan or equal to a preset first threshold value corresponding to aheight of the moving object, based on relative position information ofthe nearby objects comprised in the detection information; and selectthe still object from among the filtered nearby objects, based onvelocity information of the moving object comprised in the positioninformation and relative velocity information of the nearby objectscomprised in the detection information.

For the selecting of the still object, the one or more processors may beconfigured to: filter out nearby objects of which an angle formed withthe moving object is greater than or equal to a preset second thresholdvalue, based on relative position information of the nearby objectscomprised in the detection information; and select the still object fromamong the filtered nearby objects, based on velocity information of themoving object comprised in the position information and relativevelocity information of the nearby objects comprised in the detectioninformation.

For the updating of the point cloud, the one or more processors may beconfigured to: set a region of interest (ROI) of traveling of the movingobject based on the position information of the moving object; andfilter out a point cloud corresponding to a still object that is notcomprised in the ROI among point clouds corresponding to still objectsselected through the selecting.

For the generating of the grid map, the one or more processors may beconfigured to generate a moving path of the moving object correspondingto the still object based on the grid map.

In another general aspect, a method with grid map generation includes:determining a first point cloud of a nearby object using a radiodetection and ranging (radar) sensor at a first position; transformingcoordinates of the first point cloud based on a second position of theradar sensor; determining a second point cloud of the nearby objectusing the radar sensor at the second position; determining an updatedpoint cloud of the nearby object based on the second point cloud and thetransformed first point cloud; and generating a grid map based on anoccupancy probability for each grid of the updated point cloud.

The nearby object may be a stationary object and the radar sensor may bea moving object.

The determining of the first point cloud may include determining thefirst point cloud in response to determining that a difference betweenan absolute value of a relative velocity of the nearby object and anabsolute value of the velocity of the radar sensor is less than or equalto a preset threshold value.

The determining of the first point cloud may include determining thefirst point cloud in response to determining that either one or both of:a height of the nearby object is less than or equal to a preset firstthreshold value; and an angle between a direction of movement of theradar sensor and a direction from the radar sensor to the nearby objectis less than or equal to a preset second threshold value.

Other features and aspects will be apparent from the following detaileddescription, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a grid map generating method.

FIG. 2 illustrates an example of detection information obtained based ona radio detection and ranging (radar) sensor of a moving object.

FIG. 3 illustrates an example of a method of updating a point cloud.

FIGS. 4A through 4D illustrate examples of transforming coordinates of apoint cloud based on a displacement of a moving object in each timestep.

FIGS. 5A through 5C illustrate examples of generating a second pointcloud in each step.

FIGS. 6A through 6C illustrate examples of obtaining an updated pointcloud corresponding to each time step.

FIGS. 7A through 7C illustrate examples of generating a grip map in eachtime step.

FIG. 8 illustrates an example of a grid map generating apparatus.

Throughout the drawings and the detailed description, unless otherwisedescribed or provided, the same drawing reference numerals will beunderstood to refer to the same elements, features, and structures. Thedrawings may not be to scale, and the relative size, proportions, anddepiction of elements in the drawings may be exaggerated for clarity,illustration, and convenience.

DETAILED DESCRIPTION

The following detailed description is provided to assist the reader ingaining a comprehensive understanding of the methods, apparatuses,and/or systems described herein. However, various changes,modifications, and equivalents of the methods, apparatuses, and/orsystems described herein will be apparent after an understanding of thedisclosure of this application. For example, the sequences of operationsdescribed herein are merely examples, and are not limited to those setforth herein, but may be changed as will be apparent after anunderstanding of the disclosure of this application, with the exceptionof operations necessarily occurring in a certain order. Also,descriptions of features that are known after an understanding of thedisclosure of this application may be omitted for increased clarity andconciseness.

The features described herein may be embodied in different forms and arenot to be construed as being limited to the examples described herein.Rather, the examples described herein have been provided merely toillustrate some of the many possible ways of implementing the methods,apparatuses, and/or systems described herein that will be apparent afteran understanding of the disclosure of this application.

The terminology used herein is for describing various examples only andis not to be used to limit the disclosure. The articles “a,” “an,” and“the” are intended to include the plural forms as well, unless thecontext clearly indicates otherwise. The terms “comprises,” “includes,”and “has” specify the presence of stated features, numbers, operations,members, elements, and/or combinations thereof, but do not preclude thepresence or addition of one or more other features, numbers, operations,members, elements, and/or combinations thereof.

Throughout the specification, when an element, such as a layer, region,or substrate, is described as being “on,” “connected to,” or “coupledto” another element, it may be directly “on,” “connected to,” or“coupled to” the other element, or there may be one or more otherelements intervening therebetween. In contrast, when an element isdescribed as being “directly on,” “directly connected to,” or “directlycoupled to” another element, there can be no other elements interveningtherebetween. Likewise, each of expressions, for example, “between” and“immediately between” and “adjacent to” and “immediately adjacent to,”should also be respectively construed in the same way. As used herein,the term “and/or” includes any one and any combination of any two ormore of the associated listed items. The use of the term “may” hereinwith respect to an example or embodiment (e.g., as to what an example orembodiment may include or implement) means that at least one example orembodiment exists where such a feature is included or implemented, whileall examples are not limited thereto.

Although terms such as “first,” “second,” and “third” may be used hereinto describe various members, components, regions, layers, or sections,these members, components, regions, layers, or sections are not to belimited by these terms. Rather, these terms are only used to distinguishone member, component, region, layer, or section from another member,component, region, layer, or section. Thus, a first member, component,region, layer, or section referred to in the examples described hereinmay also be referred to as a second member, component, region, layer, orsection without departing from the teachings of the examples.

Unless otherwise defined, all terms, including technical and scientificterms, used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure pertains and basedon an understanding of the disclosure of the present application. Terms,such as those defined in commonly used dictionaries, are to beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and the disclosure of the presentapplication and are not to be interpreted in an idealized or overlyformal sense unless expressly so defined herein.

Also, in the description of example embodiments, detailed description ofstructures or functions that are thereby known after an understanding ofthe disclosure of the present application will be omitted when it isdeemed that such description will cause ambiguous interpretation of theexample embodiments. Hereinafter, examples will be described in detailwith reference to the accompanying drawings, and like reference numeralsin the drawings refer to like elements throughout.

FIG. 1 illustrates an example of a grid map generating method.

A method and apparatus of one or more embodiments may recognize anenvironment around a vehicle using a radar system instead of anexpensive lidar system. Referring to FIG. 1 , a grid map generatingmethod of example embodiments may include operation 110 of obtaining(e.g., determining) position information of a moving objectcorresponding to a first time step based on a position sensor of themoving object, operation 120 of obtaining detection informationassociated with nearby objects present around the moving objectcorresponding to the first time step based on a radio detection andranging (radar) sensor of the moving object, operation 130 of selectinga still object in a moving range of the moving object from among thenearby objects based on the position information and the detectioninformation, operation 140 of updating a point cloud obtained based onthe radar sensor in a previous time step based on the positioninformation and detection information associated with the still object,and operation 150 of generating a grid map based on an occupancyprobability for each grid of the updated point cloud. A radar sensordescribed herein may also be simply referred to as a “radar” and mayalso be provided in the form of a system, and similarly a lightdetection and ranging (lidar) sensor described herein may also be simplyreferred to as a “lidar” and may also be provided in the form of asystem.

The operations of the grid map generating method of one or moreembodiments may be performed by one or more processors of an apparatusor device of one or more embodiments connected to or interworking withthe moving object. A non-limiting example configuration of the apparatusor device performing the grid map generating method will be describedhereinafter with reference to FIG. 8 .

The moving object may refer to an object of which a position changeswhile the object moves or travels, and may be or include a vehicle, forexample. The apparatus or device performing the grid map generatingmethod may be the moving object, include the moving object, and/or beincluded in the moving object. The moving object may include one or moresensors (for example, a position sensor and/or a radar). In an example,information obtained from the sensor provided in the moving object maybe processed by the processor performing a moving path controllingmethod, and the obtaining of the information sensed by the sensor andthe processing of the obtained information may be performed repeatedly.A unit in which information is obtained by the sensor and/or theobtained information is processed by the processor may be referred toherein as a time step.

In an example, operation 110 may include obtaining the positioninformation of the moving object corresponding to the first time stepbased on one or more position sensors provided in the moving object. Thefirst time step may correspond to a current time step in whichoperations 110 through 150 are performed. In an example, operations 110through 150 are performed for each of a plurality of time steps.

The position sensor provided in the moving object may be a sensorconfigured to sense a physical quantity associated with (e.g.,indicating or corresponding to) a position of the moving object, forexample, the position information, displacement information, andvelocity information of the moving object. For example, the positionsensor provided in the moving object may be used to obtain velocityinformation of the moving object, yaw rate information of the movingobject, and/or global positioning system (GPS) information of the movingobject. That is, operation 110 of obtaining position information of amoving object may include obtaining any one or any combination of anytwo or more of velocity information, yaw rate information, and GPSinformation of the moving object corresponding to the first time step.

In an example, operation 120 may include obtaining the detectioninformation associated with the nearby objects present around the movingobject corresponding to the first time step, based on one or more radarsprovided in the moving object. The radar provided in the moving objectmay refer to a sensor configured to measure the distance, direction,angle, and velocity of a nearby object by emitting a radio wave andanalyzing an electromagnetic wave returning after the emitted radio waveis reflected by the nearby object.

The radio wave emitted from the radar may be reflected by a point on onesurface of the nearby object, and the radar may obtain detectioninformation associated with the point by analyzing the electromagneticwave reflected by the point. For example, the moving object may includeone or more radar sensors. In this example, when radio waves emittedfrom the radar sensors are reflected from one or more points on onesurface of a nearby object for a first time step, detection informationassociated with the points may be obtained. Based on this detectioninformation associated with the points collected by the radar sensors, aset of the points may be recognized as the nearby object.

In an example, based on the radar provided in the moving object,relative position information of the nearby objects and/or relativevelocity information of the nearby objects with respect to the radar maybe obtained. That is, operation 120 may include obtaining either one orboth of relative position information of the nearby objects and relativevelocity information of the nearby objects with respect to the radarcorresponding to the first time step. The detection informationassociated with the nearby objects may include detection informationassociated with one or more points on a surface of a nearby object fromwhich a radio wave is reflected.

For example, referring to FIG. 2 , a radar 202 (e.g., a radar sensor)provided in a moving object 201 may emit a radio wave, and obtaindetection information associated with a nearby object 203 based on anelectromagnetic wave returning after the radio wave is reflected by thenearby object 203. In this example, the detection information mayinclude detection information associated with one or more points 204 onone surface of the nearby object 203 from which the radio wave emittedfrom the radar 202 is reflected.

For example, the detection information obtained as the radio waveemitted from the radar 202 is reflected by the point 204 on the surfaceof the nearby object 203 may include information associated with adistance 210 between the radar 202 and the point 204 and informationassociated with an angle 230 of the point 204 with respect to the radar202 (e.g., with respect to a direction of movement of the radar 202).Based on the information associated with the distance 210 and theinformation associated with the angle 230, relative positions of thepoint 204 and the radar 202 may be determined.

For another example, the detection information obtained as the radiowave emitted from the radar 202 is reflected by the point 204 on thesurface of the nearby object 203 may include information associated witha relative velocity 220 of the point 204 with respect to the radar 202.In this example, when the nearby object 203 is in a stationary state andthe moving object 201 moves forward at a velocity 240, the point 204 ofthe nearby object 203 may be detected as moving backward with respect tothe radar 202 at the velocity 220.

Referring back to FIG. 1 , operation 130 may include selecting ordetermining a still object with an unchanged position from among thenearby objects present around the moving object, based on the positioninformation obtained in operation 110 and the detection informationassociated with the nearby objects obtained in operation 120. Whether anearby object is a still object or not may be determined based on arelative velocity of a nearby object detected by the radar and onvelocity information of the moving object. For example, when a relativevelocity of a nearby object detected by the radar is the same as avelocity of the moving object in magnitude (or when a difference betweenan absolute value of the relative velocity of the nearby object and anabsolute value of the velocity of the moving object is less than orequal to a threshold value) but opposite to the velocity of the movingobject in direction, the nearby object may be determined to be a stillobject because the relative velocity of the nearby object occurs by thevelocity of the moving object. For example, when the moving object movesat a velocity of 10 kilometers per hour (km/h) based on the velocityinformation of the moving object, and a nearby object moves at avelocity of 10 km/h in an opposite direction to that of the movingobject based on relative velocity information of the nearby objectdetected by the radar, the nearby object may be determined to be a stillobject because the relative velocity of the nearby object occurs by themovement of the moving object.

In an example, operation 130 of selecting a still object may includefiltering out nearby objects positioned at a height greater than orequal to a preset first threshold value corresponding to a height of themoving object based on the relative position information of the nearbyobjects included in the detection information, and selecting a stillobject from among the filtered nearby objects based on the velocityinformation of the moving object included in the position informationand the relative velocity information of the nearby objects included inthe detection information. The first threshold value may be set inadvance based on a standard for whether the moving object passes or not.For example, the first threshold value may include a lower limit of aheight of the moving object by which the moving object may pass based onthe height of the moving object.

The filtering of the nearby objects positioned at the height greaterthan or equal to the first threshold value may indicate excluding thenearby objects positioned at the height greater than or equal to thefirst threshold value from targets to be selected as a still object. Anearby object positioned at the height greater than or equal to thefirst threshold value may be excluded in such filtering operation, andthus the nearby object may not be selected as a still object even thoughthe nearby object is in a stationary state. For example, in a case of atraffic light installed on a road, the traffic light may be excludedfrom a target to be selected as a still object because the traffic lightis positioned at a height by which a vehicle may pass even though thetraffic light is a still object being in a stationary state. That is, anearby object by which the moving object may pass may be excludedthrough the filtering in such an object selecting operation, and it isthus possible to reduce an unnecessary operation for an object that isnot considered when generating a moving path of the moving object.

In an example, operation 130 of selecting a still object may includefiltering out nearby objects of which an angle formed with the movingobject is greater than or equal to a preset second threshold value basedon the relative position information of the nearby objects included inthe detection information, and selecting a still object from among thefiltered nearby objects based on the velocity information of the movingobject included in the position information and on the relative velocityinformation of the nearby objects included in the detection information.The second threshold value may be determined based on a range of anglesfrom which whether a nearby object is stationary is determined or arange of angles having a great probability of being included in themoving range of the moving object.

For example, in a case of a nearby object of which an angle with themoving object is 90 degrees (°), that is, a nearby object positioned ona left or right side of the moving object, whether the nearby object isa still object or a moving object may not be readily determined, andthus the nearby object may be filtered out in operation 130.

In an example, operation 140 may include updating a point cloud obtainedbased on the radar of the moving object in a previous time step(hereinafter also referred to as a “second time step”) of the first timestep, based on the position information and on detection informationassociated with the still object selected in operation 130 that isincluded in the detection information associated with the nearbyobjects.

The point cloud may be a set of points in a coordinate system thatrepresents the surface of an object sensed by the sensor and mayinclude, for example, a set of points defined as x, y, and z coordinatesin a 3D coordinate system corresponding to the surface of an objectsensed by the radar. The point cloud may be generated based on a signalsensed by the radar provided in the moving object, and may include a setof one or more points corresponding to the sensed signal in a 3Dcoordinate system having a position of the moving object as a referencepoint. The signal sensed by the radar may include relative positioninformation of a point obtained based on an electromagnetic waveobtained as a radio wave emitted from the radar strikes on a point onthe surface of an object and is reflected therefrom.

In an example, the point cloud having the position of the moving objectas a reference point may be generated based on relative positioninformation of points detected by the radar. The relative positioninformation of the points detected by the radar may be transformed withrespect to the position of the moving object as a reference, based on arelative position relationship between the radar and the moving object.For example, the relative position information of the points detected bythe radar may correspond to relative position information obtained basedon the radar, and thus the relative position information of the detectedpoints may be transformed with respect to the position corresponding toa center of the moving object, based on a position of the radar in themoving object in which the radar is provided. That is, detectioninformation associated with a nearby object obtained based on the radarof the moving object may include relative position information of thenearby object with respect to a position of the radar. In addition,operation 140 of updating a point cloud may further include transformingthe relative position information of the still object included in thedetection information based on the position of the moving object, basedon the relative position relationship of the radar provided in themoving object and the moving object.

A non-limiting example of operation 140 of updating a point cloud willbe described in detail with reference to FIG. 3 . Referring to FIG. 3 ,an operation (e.g., operation 140 of FIG. 1 ) of updating a point cloudmay include operation 310 of transforming coordinates of a first pointcloud obtained in a previous time step, with respect to a position of amoving object in a first time step obtained based on positioninformation of the moving object, operation 320 of generating a secondpoint cloud corresponding to a still object based on detectioninformation associated with the still object obtained in the first timestep, and operation 330 of obtaining an updated point cloudcorresponding to the first time step by accumulating the second pointcloud with the transformed first point cloud.

In an example, the first point cloud obtained in operation 310 maycorrespond to a point cloud obtained in operation (e.g., operation 140of FIG. 1 ) of updating a point cloud corresponding to the second timestep. The first point cloud may include a set of points corresponding toa still object selected in the second time step in a 3D coordinatesystem having a position of the moving object in the second time step asan origin point.

In an example, in operation 310, coordinates of the first point cloudmay be transformed with respect to the position of the moving object inthe first time step. The position of the moving object in the first timestep may be obtained based on the position information of the movingobject corresponding to the first time step, for example, the positioninformation of the moving object obtained in operation 110 of FIG. 1 .The coordinates of the first point cloud may be transformed based on adisplacement of the moving object. For example, the displacement of themoving object may correspond to a vector corresponding to a differencebetween the position of the moving object in the first time step and theposition of the moving object in the second time step, and thecoordinates of the first point cloud in the first time step may betransformed in a direction opposite to the displacement of the movingobject.

For example, when there is no previous time step of the first time step,that is, when the first time step corresponds to an initial time step inwhich operations 110 through 150 of FIG. 1 are performed initially,there may be no point cloud obtained in the previous time point. Thus,an operation (e.g., operation 140 of FIG. 1 ) of updating a point cloudcorresponding to the initial time step may include operation 320 ofgenerating a point cloud corresponding to the still object based on thedetection information associated with the still object obtained in thefirst time step. That is, the operation (e.g., operation 140 of FIG. 1 )of updating the point cloud corresponding to the initial time step mayinclude operation 320 of generating a second point cloud correspondingto the still object based on relative position information of the stillobject obtained by the radar in a current time step, without operation310 of transforming the coordinates of the first point cloud obtained inthe previous time step. The second point cloud generated in operation320 may correspond to an updated point cloud corresponding to thecurrent time step.

For example, referring to FIG. 4A, a point cloud 410 obtained in a timestep t0 corresponding to an initial time step may be obtained based ondetection information associated with a still object obtained by aradar. For example, based on relative position information of the stillobject obtained from the radar, the point cloud 410 including a point411 corresponding to the still object in a coordinate system having apreset position of a moving object as a reference point 401 may begenerated.

In an example, operation 140 corresponding to a subsequent time step ofthe initial time step may include transforming coordinates of a pointcloud obtained in a previous time step based on a displacement of amoving object. For example, referring to FIG. 4B, a coordinate 411 of apoint included in a point cloud obtained in a time step t0 may betransformed into a coordinate 421 based on a displacement 422 of amoving object in a subsequent time step t1 of the time step t0, and atransformed point cloud 420 may be obtained. For example, as the movingobject moves by a in a y direction in the time step t1, a coordinate ofa point cloud may be transformed by −a in the y direction. That is, thepoint cloud obtained in the time step t0 may be transformed into acoordinate corresponding to a coordinate system having a position of themoving object changed in the time step t1 as the reference point 401.

Referring to FIG. 4C, the coordinate 421 of a point included in a pointcloud obtained in the time step t1 may be transformed into a coordinate431 based on a displacement 432 of the moving object in a subsequenttime step t2 of the time step t1, and a transformed point cloud 430 maybe obtained. Referring to FIG. 4D, the coordinate 431 of a pointincluded in a point cloud obtained in the time step t2 may betransformed into a coordinate 441 based on a displacement of the movingobject in a subsequent time step t3 of the time step t2, and atransformed point cloud 440 may be obtained.

In an example, information associated with a displacement of a movingobject in each time step may be accumulated, and information associatedwith a moving path of the moving object may be obtained. For example,referring to FIG. 4D, the displacements of the moving object in the timesteps t0 through t3 may be accumulated, and information associated witha moving path of the moving object including a vector (t0, t1), a vector(t1, t2), and a vector (t2, t3) may be obtained.

Although the point clouds 410, 420, 430, and 440 each including onepoint are illustrated in FIGS. 4A through 4D, a point cloud obtained ineach time step may include one or more points corresponding to one ormore still objects. In addition, although a point cloud is illustratedin the form of a map corresponding to a 2D coordinate system in FIGS. 4Athrough 4D, the point cloud may be obtained in the form of anarrangement of coordinate values of points included in the point cloud.

Referring back to FIG. 3 , the operation (e.g., operation 140 of FIG. 1) of updating a point cloud may include operation 320 of generating asecond point cloud corresponding to a still object based on detectioninformation associated with the still object obtained in a first timestep. The second point cloud may be generated based on detectioninformation associated with a still object selected in operation 130 ofFIG. 1 that is included in detection information obtained based on aradar in the first time step. For example, the second point cloudincluding a set of points corresponding to a still object in a 3Dcoordinate system having a position of a moving object in the first timestep as an origin point may be generated based on relative positioninformation of the still object obtained from the radar.

For example, referring to FIG. 5A, based on relative positioninformation of three detected points 510 on the surface of a stillobject 503 obtained based on a radar 502 of a moving object 501 in atime step t0, a second point cloud corresponding to the three detectedpoints 510 may be generated. Referring to FIG. 5B, a position of themoving object 501 may be changed in a time step t1. Based on relativeposition information of five detected point 520 on the surface of thestill object 503 obtained based on the radar 502 of the moving object501, a second point cloud corresponding to the five detected points 520may be generated. Referring to FIG. 5C, a position of the moving object501 may be changed in a time step t2. Based on relative positioninformation of three detected points 530 on the surface of the stillobject 503 obtained based on the radar 502 of the moving object 501, asecond point cloud corresponding to the three detected points 530 may begenerated.

Referring to FIGS. 5A through 5C, detected points on the surface of thestill object 503 obtained from the radar 502 of the moving object 501 ineach time step may be different. That is, as illustrated in FIGS. 5Athrough 5C, at least a portion of the three detected points 510 obtainedfrom the radar 502 of the moving object 501 in the time step t0 when thestill object 503 is positioned in front of the moving object 501, thefive detected points 520 obtained from the radar 502 of the movingobject 501 in the time step t1 when the still object 503 is positionedon a side of the moving object 501, and the three detected points 530obtained from the radar 502 of the moving object 501 in the time step t2when the still object 503 is positioned behind the moving object 501 maybe different.

Referring back to FIG. 3 , the operation (e.g., operation 140 of FIG. 1) of updating a point cloud may include operation 330 of obtaining anupdated point cloud corresponding to a first time step by accumulating asecond point cloud with a transformed first point cloud. For example,FIGS. 6A through 6C illustrate examples of a point cloud updated basedon a second point cloud illustrated in FIGS. 5A through 5C. For example,FIG. 6A illustrates an example of an updated point cloud correspondingto a time step t0 which is a first time step, and the updated pointcloud may be the same as a second point cloud corresponding to the timestep t0 illustrated in FIG. 5A. FIG. 6B illustrates an example of anupdated point cloud corresponding to a time step t1 which is asubsequent time step of the time step t0, and the updated point cloudmay include a transformed first point cloud obtained as coordinates of afirst point cloud obtained in the time step t0 illustrated in FIG. 6A istransformed based on a displacement of a moving object and include asecond point cloud (the same as a second point cloud illustrated in FIG.5B) that is generated based on detection information associated with astill object obtained in the time step t1. FIG. 6C illustrates anexample of an updated point cloud corresponding to a time step t2 whichis a subsequent time step of the time step t1, and the updated pointcloud may include a transformed first point cloud obtained ascoordinates of a first point cloud obtained in the time step t1illustrated in FIG. 6B is transformed based on a displacement of themoving object and include a second point cloud (the same as a secondpoint cloud illustrated in FIG. 5C) that is generated based on detectioninformation associated with a still object obtained in the time step t2.

In an example, an updated point cloud corresponding to a first time stepmay be a point cloud obtained as a point cloud obtained in a second timestep is updated based on detection information associated with a stillobject obtained in the first time step, and may correspond to a pointcloud obtained in the first time step. The updated point cloudcorresponding to the first time step may correspond to a point cloudobtained in a previous time step in the operation (e.g., operation 140of FIG. 1 ) of updating a point cloud corresponding to a subsequent timestep of the first time step, and may be updated based on positioninformation of a moving object and detection information of a stillobject that are obtained in the subsequent time step.

Referring back to FIG. 3 , the operation (e.g., operation 140 of FIG. 1) of updating a point cloud may further include an operation of removinga first point cloud obtained in a second time step, after operation 330of obtaining an updated point cloud corresponding to a first time step.Since the updated point cloud corresponding to the first time step isobtained based on a transformed first point cloud corresponding to thefirst time step, removing the first point cloud corresponding to aprevious time step from a memory may advantageously reduce the size ofdata to be stored in the memory.

Referring back to FIG. 1 , operation 140 may further include setting aregion of interest (ROI) for traveling of the moving object based on theposition information of the moving object obtained in operation 110, andfiltering out a point cloud corresponding to a still object that is notincluded in the ROI among point clouds corresponding to still objectsselected in operation 130. The ROI may be a region that is likely to beincluded in a moving path of the moving object. For example, a stillobject that is positioned in an opposite direction of a moving directionof the moving object and is at a position separate from the movingobject by a preset distance may be determined not to be included in themoving path of the moving object, and a point cloud corresponding to thestill object may be removed from a point cloud corresponding to a firsttime step. The ROI for the traveling of the moving object may be setbased on various preset standards in addition to a standard for themoving direction of the moving object and/or a standard for a distancefrom the moving object.

In an example, operation 150 may include generating a grid map based onan occupancy probability for each grid of an updated point cloudcorresponding to a first time step obtained in operation 140. Forexample, the occupancy probability for each grid of the point cloud maybe estimated based on a distribution of points included in the pointcloud. The grid map may refer to a map representing a grid having a highprobability of being occupied by the points included in the point cloud,based on the distribution of the points included in the point cloud. Thegrid having the high probability of being occupied by the pointsincluded in the point cloud that is represented in the grid map maycorrespond to information indicating a region occupied by a still objectcorresponding to the point cloud.

For example, referring to FIG. 7A, a grid map corresponding to a set ofpoints included in a point cloud illustrated in FIG. 6A may begenerated. The grid map may correspond to a map representing a grid 710having a high probability of being occupied by the points included inthe point cloud based on a distribution of the points included in thepoint cloud of FIG. 6A. For another example, referring to FIG. 7B, agrid map corresponding to a set of points included in a point cloudillustrated in FIG. 6B may be generated. For still another example,referring to FIG. 7C, a grid map corresponding to a set of pointsincluded in a point cloud illustrated in FIG. 6C may be generated.

Referring to FIG. 7B, there is a region of a grid 720 that is similar toa region actually occupied by a still object corresponding to the pointcloud, compared to the grid map illustrated in FIG. 7A. That is, thegrid map generating method and apparatus of one or more embodiments maygenerate a more accurate grid map by updating a point cloudcorresponding to a current time step by applying a point cloud obtainedin a previous time step.

Referring back to FIG. 1 , operation 150 may further include generatinga moving path of the moving object corresponding to the still object,based on the generated grid map. For example, the generating of themoving path of the moving object may include generating the moving pathof the moving object that detours a space occupied by the still objectbased on the grid map generated in operation 150. The moving path of themoving object that detours the space occupied by the still object mayinclude a path through which the moving object detours the spaceoccupied by the still object and is then returned to the original movingpath.

For another example, the generating of the moving path of the movingobject may include generating the moving path of the moving object thatdetours the space occupied by the still object based on the grid mapgenerated in operation 150. The moving path of the moving object thatdetours the space occupied by the still object may include a pathchanged such that the moving object detours the space occupied by thestill object, and the changed path may be maintained afterward.

FIG. 8 illustrates an example of a grid map generating apparatus.

Referring to FIG. 8 , a grid map generating apparatus 800 may include aprocessor 801 (e.g., one or more processors), a memory 803 (e.g., one ormore memories), an input and output (I/O) device 805, and a sensor 807(e.g., one or more sensors). The grid map generating apparatus 800 mayperform the grid map generating method described herein and may include,for example, a server communicating with a moving object and/or a deviceprovided in the moving object. In an example, the grid map generatingapparatus 800 may be the moving object, include the moving object,and/or be included in the moving object.

The processor 801 may perform any one or more, or all, of the operationsand methods described herein with reference to FIGS. 1 through 7 . In anexample, the processor 801 may obtain detection information associatedwith nearby objects from a radar provided in a moving object, and obtainposition information of the moving object from a position sensor (e.g.,of the sensor 807) provided in the moving object. The processor 801 mayperform the operations or methods described above with reference toFIGS. 1 through 7 to generate a grid map based on the obtained detectioninformation and the obtained position information. The processor 801 mayfurther perform an operation of generating a moving path of the movingobject based on the generated grid map.

The memory 803 may be a volatile or nonvolatile memory. The memory 803may store therein information associated with the grid map generatingmethod described herein. For example, the memory 803 may store thereinany one or any combination of any two or more of position information ofthe moving object obtained in a current time step, detection informationassociated with nearby objects, a point cloud, and a grid map.

The grid map generating apparatus 800 may be connected to an externaldevice (e.g., a personal computer (PC) or a network) through the I/Odevice 805, and exchange data with the external device through the I/Odevice 805. For example, the grid map generating apparatus 800 mayreceive a signal sensed from the position sensor and/or the radar (e.g.,of the sensor 807) provided in the moving object, and output a generatedgrid map and/or a moving path of the moving object generated based onthe grid map, through the I/O device 805. Although not illustrated inFIG. 8 , the grid map generating apparatus 800 may further include acommunication interface for communication with an external device, andcommunication with a sensor (e.g., the sensor 807) provided in themoving object may be performed through the communication interface.

The sensor 807 may be or include any one or more or all of the sensors,position sensors, radars, and lidars described herein with reference toFIGS. 1 through 7 .

The memory 803 may store a program that implements the grid mapgenerating method. The processor 801 may execute the program stored inthe memory 803 and control the grid map generating apparatus 800. A codeof the program executed by the processor 801 may be stored in the memory803.

The grid map generating apparatuses, moving objects, radars, processors,memories, I/O devices, sensors, moving object 201, radar 202, movingobject 501, radar 502, grid map generating apparatus 800, processor 801,memory 803, I/O device 805, sensor 807, and other apparatuses, devices,units, modules, and components described herein with respect to FIGS.1-8 are implemented by or representative of hardware components.Examples of hardware components that may be used to perform theoperations described in this application where appropriate includecontrollers, sensors, generators, drivers, memories, comparators,arithmetic logic units, adders, subtractors, multipliers, dividers,integrators, and any other electronic components configured to performthe operations described in this application. In other examples, one ormore of the hardware components that perform the operations described inthis application are implemented by computing hardware, for example, byone or more processors or computers. A processor or computer may beimplemented by one or more processing elements, such as an array oflogic gates, a controller and an arithmetic logic unit, a digital signalprocessor, a microcomputer, a programmable logic controller, afield-programmable gate array, a programmable logic array, amicroprocessor, or any other device or combination of devices that isconfigured to respond to and execute instructions in a defined manner toachieve a desired result. In one example, a processor or computerincludes, or is connected to, one or more memories storing instructionsor software that are executed by the processor or computer. Hardwarecomponents implemented by a processor or computer may executeinstructions or software, such as an operating system (OS) and one ormore software applications that run on the OS, to perform the operationsdescribed in this application. The hardware components may also access,manipulate, process, create, and store data in response to execution ofthe instructions or software. For simplicity, the singular term“processor” or “computer” may be used in the description of the examplesdescribed in this application, but in other examples multiple processorsor computers may be used, or a processor or computer may includemultiple processing elements, or multiple types of processing elements,or both. For example, a single hardware component or two or morehardware components may be implemented by a single processor, or two ormore processors, or a processor and a controller. One or more hardwarecomponents may be implemented by one or more processors, or a processorand a controller, and one or more other hardware components may beimplemented by one or more other processors, or another processor andanother controller. One or more processors, or a processor and acontroller, may implement a single hardware component, or two or morehardware components. A hardware component may have any one or more ofdifferent processing configurations, examples of which include a singleprocessor, independent processors, parallel processors,single-instruction single-data (SISD) multiprocessing,single-instruction multiple-data (SIMD) multiprocessing,multiple-instruction single-data (MISD) multiprocessing, andmultiple-instruction multiple-data (MIMD) multiprocessing.

The methods illustrated in FIGS. 1-8 that perform the operationsdescribed in this application are performed by computing hardware, forexample, by one or more processors or computers, implemented asdescribed above executing instructions or software to perform theoperations described in this application that are performed by themethods. For example, a single operation or two or more operations maybe performed by a single processor, or two or more processors, or aprocessor and a controller. One or more operations may be performed byone or more processors, or a processor and a controller, and one or moreother operations may be performed by one or more other processors, oranother processor and another controller. One or more processors, or aprocessor and a controller, may perform a single operation, or two ormore operations.

Instructions or software to control computing hardware, for example, oneor more processors or computers, to implement the hardware componentsand perform the methods as described above may be written as computerprograms, code segments, instructions or any combination thereof, forindividually or collectively instructing or configuring the one or moreprocessors or computers to operate as a machine or special-purposecomputer to perform the operations that are performed by the hardwarecomponents and the methods as described above. In one example, theinstructions or software include machine code that is directly executedby the one or more processors or computers, such as machine codeproduced by a compiler. In another example, the instructions or softwareincludes higher-level code that is executed by the one or moreprocessors or computer using an interpreter. The instructions orsoftware may be written using any programming language based on theblock diagrams and the flow charts illustrated in the drawings and thecorresponding descriptions in the specification, which disclosealgorithms for performing the operations that are performed by thehardware components and the methods as described above.

The instructions or software to control computing hardware, for example,one or more processors or computers, to implement the hardwarecomponents and perform the methods as described above, and anyassociated data, data files, and data structures, may be recorded,stored, or fixed in or on one or more non-transitory computer-readablestorage media. Examples of a non-transitory computer-readable storagemedium include read-only memory (ROM), random-access programmable readonly memory (PROM), electrically erasable programmable read-only memory(EEPROM), random-access memory (RAM), dynamic random access memory(DRAM), static random access memory (SRAM), flash memory, non-volatilememory, CD-ROMs, CD-Rs, CD+Rs, CD-RWs, CD+RWs, DVD-ROMs, DVD-Rs, DVD+Rs,DVD-RWs, DVD+RWs, DVD-RAMs, BD-ROMs, BD-Rs, BD-R LTHs, BD-REs, blue-rayor optical disk storage, hard disk drive (HDD), solid state drive (SSD),flash memory, a card type memory such as multimedia card micro or a card(for example, secure digital (SD) or extreme digital (XD)), magnetictapes, floppy disks, magneto-optical data storage devices, optical datastorage devices, hard disks, solid-state disks, and any other devicethat is configured to store the instructions or software and anyassociated data, data files, and data structures in a non-transitorymanner and provide the instructions or software and any associated data,data files, and data structures to one or more processors or computersso that the one or more processors or computers can execute theinstructions. In one example, the instructions or software and anyassociated data, data files, and data structures are distributed overnetwork-coupled computer systems so that the instructions and softwareand any associated data, data files, and data structures are stored,accessed, and executed in a distributed fashion by the one or moreprocessors or computers.

While this disclosure includes specific examples, it will be apparentafter an understanding of the disclosure of this application thatvarious changes in form and details may be made in these exampleswithout departing from the spirit and scope of the claims and theirequivalents. The examples described herein are to be considered in adescriptive sense only, and not for purposes of limitation. Descriptionsof features or aspects in each example are to be considered as beingapplicable to similar features or aspects in other examples. Suitableresults may be achieved if the described techniques are performed in adifferent order, and/or if components in a described system,architecture, device, or circuit are combined in a different manner,and/or replaced or supplemented by other components or theirequivalents.

What is claimed is:
 1. A method with grid map generation, comprising:determining position information of a moving object corresponding to afirst time step based on a position sensor of the moving object;determining detection information of nearby objects present around themoving object corresponding to the first time step based on a radiodetection and ranging (radar) sensor of the moving object; selecting astill object in a moving range of the moving object from among thenearby objects, based on the position information and the detectioninformation; updating a point cloud determined based on the radar sensorin a previous time step of the first time step, based on the positioninformation and on detection information of the still object comprisedin the detection information of the nearby objects; and generating agrid map based on an occupancy probability for each grid of the updatedpoint cloud.
 2. The method of claim 1, wherein the updating of the pointcloud comprises: transforming coordinates of a first point clouddetermined in the previous time step, with respect to a position of themoving object in the first time step determined based on the positioninformation; generating a second point cloud corresponding to the stillobject, based on detection information of the still object determined inthe first time step; and determining an updated point cloudcorresponding to the first time step by accumulating the second pointcloud with the transformed first point cloud.
 3. The method of claim 2,further comprising removing the first point cloud determined in theprevious time step.
 4. The method of claim 1, wherein the detectioninformation comprises relative position information of the nearbyobjects with respect to a position of the radar sensor, and the updatingof the point cloud further comprises transforming relative positioninformation of the still object comprised in the detection informationwith respect to a position of the moving object, based on a relativeposition relationship of the radar sensor and the moving object.
 5. Themethod of claim 1, wherein the selecting of the still object comprises:filtering out nearby objects positioned at a height greater than orequal to a preset first threshold value corresponding to a height of themoving object, based on relative position information of the nearbyobjects comprised in the detection information; and selecting the stillobject from among the filtered nearby objects, based on velocityinformation of the moving object comprised in the position informationand relative velocity information of the nearby objects comprised in thedetection information.
 6. The method of claim 1, wherein the selectingof the still object comprises: filtering out nearby objects of which anangle formed with the moving object is greater than or equal to a presetsecond threshold value, based on relative position information of thenearby objects comprised in the detection information; and selecting thestill object from among the filtered nearby objects, based on velocityinformation of the moving object comprised in the position informationand relative velocity information of the nearby objects comprised in thedetection information.
 7. The method of claim 1, wherein the updating ofthe point cloud further comprises: setting a region of interest (ROI) oftraveling of the moving object based on the position information of themoving object; and filtering out a point cloud corresponding to a stillobject that is not comprised in the ROI among point clouds correspondingto still objects selected through the selecting.
 8. The method of claim1, wherein the generating of the grid map further comprises generating amoving path of the moving object corresponding to the still object basedon the grid map.
 9. The method of claim 8, wherein the generating of themoving path of the moving object comprises generating the moving path ofthe moving object that detours a space occupied by the still object,based on the grid map.
 10. The method of claim 1, wherein thedetermining of the position information of the moving object comprisesdetermining any one or any combination of any two or more of velocityinformation of the moving object, yaw rate information of the movingobject, and global positioning system (GPS) information of the movingobject corresponding to the first time step.
 11. The method of claim 1,wherein the determining of the detection information of the nearbyobjects comprises determining either one or both of relative positioninformation of the nearby objects and relative velocity information ofthe nearby objects with respect to the radar sensor corresponding to thefirst time step.
 12. The method of claim 1, wherein the point cloud isgenerated based on a signal sensed by the radar sensor, and comprises aset of one or more points corresponding to the sensed signal in acoordinate system having a position of the moving object as a referencepoint.
 13. A non-transitory computer-readable storage medium storinginstructions that, when executed by one or more processors, configurethe one or more processors to perform the method of claim
 1. 14. Anapparatus with grid map generation, comprising: one or more processorsconfigured to: determine position information of a moving objectcorresponding to a first time step based on a position sensor of themoving object; determine detection information of nearby objects presentaround the moving object corresponding to the first time step based on aradio detection and ranging (radar) sensor of the moving object; selecta still object in a moving range of the moving object from among thenearby objects based on the position information and the detectioninformation; update a point cloud determined based on the radar sensorin a previous time step of the first time step, based on the positioninformation and detection information of the still object comprised inthe detection information of the nearby objects; and generating a gridmap based on an occupancy probability for each grid of the updated pointcloud.
 15. The apparatus of claim 14, wherein, for the updating of thepoint cloud, the one or more processors are configured to: transformcoordinates of a first point cloud determined in the previous time step,with respect to a position of the moving object in the first time stepdetermined based on the position information; generate a second pointcloud corresponding to the still object, based on detection informationof the still object determined in the first time step; and determine anupdated point cloud corresponding to the first time step by accumulatingthe second point cloud with the transformed first point cloud.
 16. Theapparatus of claim 14, wherein the detection information comprisesrelative position information of the nearby objects with respect to aposition of the radar sensor, and for the updating of the point cloud,the one or more processors are configured to transform relative positioninformation of the still object comprised in the detection informationwith respect to a position of the moving object, based on a relativeposition relationship of the radar sensor and the moving object.
 17. Theapparatus of claim 14, wherein, for the selecting of the still object,the one or more processors are configured to: filter out nearby objectspositioned at a height greater than or equal to a preset first thresholdvalue corresponding to a height of the moving object, based on relativeposition information of the nearby objects comprised in the detectioninformation; and select the still object from among the filtered nearbyobjects, based on velocity information of the moving object comprised inthe position information and relative velocity information of the nearbyobjects comprised in the detection information.
 18. The apparatus ofclaim 14, wherein, for the selecting of the still object, the one ormore processors are configured to: filter out nearby objects of which anangle formed with the moving object is greater than or equal to a presetsecond threshold value, based on relative position information of thenearby objects comprised in the detection information; and select thestill object from among the filtered nearby objects, based on velocityinformation of the moving object comprised in the position informationand relative velocity information of the nearby objects comprised in thedetection information.
 19. The apparatus of claim 14, wherein, for theupdating of the point cloud, the one or more processors are configuredto: set a region of interest (ROI) of traveling of the moving objectbased on the position information of the moving object; and filter out apoint cloud corresponding to a still object that is not comprised in theROI among point clouds corresponding to still objects selected throughthe selecting.
 20. The apparatus of claim 14, wherein, for thegenerating of the grid map, the one or more processors are configured togenerate a moving path of the moving object corresponding to the stillobject based on the grid map.
 21. A method with grid map generation,comprising: determining a first point cloud of a nearby object using aradio detection and ranging (radar) sensor at a first position;transforming coordinates of the first point cloud based on a secondposition of the radar sensor; determining a second point cloud of thenearby object using the radar sensor at the second position; determiningan updated point cloud of the nearby object based on the second pointcloud and the transformed first point cloud; and generating a grid mapbased on an occupancy probability for each grid of the updated pointcloud.
 22. The method of claim 21, wherein the nearby object is astationary object and the radar sensor is a moving object.
 23. Themethod of claim 21, wherein the determining of the first point cloudcomprises determining the first point cloud in response to determiningthat a difference between an absolute value of a relative velocity ofthe nearby object and an absolute value of the velocity of the radarsensor is less than or equal to a preset threshold value.
 24. The methodof claim 21, wherein the determining of the first point cloud comprisesdetermining the first point cloud in response to determining that eitherone or both of: a height of the nearby object is less than or equal to apreset first threshold value; and an angle between a direction ofmovement of the radar sensor and a direction from the radar sensor tothe nearby object is less than or equal to a preset second thresholdvalue.